1. Field of the Invention
This invention relates to an emergency security device particularly adapted to be used on a head of a leaking gas cylinder containing a toxic and/or corrosive gas.
2. Description of the Prior Art
The extensive use of toxic and corrosive gases in the industry has led to increasing government regulations on the handling of gas cylinders, with a special emphasis on emergency situations, such as leaks from the cylinder and particularly from the head part of such a cylinder. Up to now, three major devices have been designed and sold for use in controlling leaking gas cylinders.
a. Chlorine Institute Emergency Kit "A"
The chlorine kit "A" contains a pressure cap assembly which can seal the valve assembly of a chlorine cylinder with the use of a set of chains connected to the base of the cylinder. Such a device is effective but limited to use on low vapor pressure gases, such as sulfur dioxide or chlorine. It cannot be used for higher vapor pressure, such as arsine (1515 KPa) or hydrogen chloride (4330 KPa).
b. Cylinder Containment Vessel
In this case, such as disclosed in U.S. Pat. No. 4,494,666, the leaking gas cylinder is completely introduced into a high pressure containment vessel which is then tranported back to a safe area for disposal. However, these vessels are expensive and for larger cylinders they are heavy and cumbersome. The weight and size of these vessels prevents the ease of use in areas where a leaking cylinder may be. Moreover, it also makes it inconvenient for it to be carried, for example, on a delivery truck for immediate use.
c. Ventilated Gas Cabinets
Ventilated gas cabinets, such as described in U.S. Pat. No. 4,625,627, are routinely used in the Electronic Gas industry to safely contain cylinders during use. A typical cabinet is constructed of welded sheets of metal and is exhausted at the top. Leaking gas escaping from cylinders is rapidly diluted with air and exhausted to an appropriate treatment system. In all cases, the gas cabinets are fixed installations which require support facilities, such as fans and scrubbers. For emergency situations, unless a gas cabinet is nearby it cannot be setup immediately for use.